Japanese Encephalitis (JE)

Japanese Encephalitis (in-cef-a-LY-tus), or JE, is common in Asia. JE can cause encephalitis (inflammation of the brain), which can be deadly. JE is not found in the United States — and thanks to the JE vaccine, travelers rarely get the disease.

The JE vaccine is only recommended for people who live in or travel to parts of Asia where JE is a risk.

JE is caused by a virus. Most people who get JE have no symptoms or very mild symptoms, like a headache and low fever. But about 1 in 250 people will develop more serious symptoms, like:

High fever

Headache

Throwing up

Feeling dizzy or confused

Seizures

Difficulty moving or paralysis

As many as 1 in 3 people can die from JE. Complications from JE can also cause permanent disability — in fact, as many as 1 in 3 people who get JE can end up with a disability.

JE does not spread from person to person, like through touching or kissing. The virus that causes JE is spread by mosquitoes, so people get it when they’re bitten by an infected mosquito. Learn more about JE.

You may need the JE vaccine if you’ll be living in or traveling to an area in Asia and you:

Plan to spend 1 month or more in a place where JE is common

Plan to spend any amount of time in a place where JE is common — and will be outdoors in rural areas or staying somewhere without air conditioning, mosquito nets, or window screens

Plan to travel in an area with an ongoing JE outbreak

Plan to spend time in a country where JE is a risk and you don’t have set plans for your trip (like which places you’ll visit or how long you’ll stay)

Travelers need 2 doses of the JE vaccine 1 month apart. Keep in mind that you’ll need to get the second dose at least 1 week before your trip. If you plan to stay in or return to Asia, you may also need a one-time booster dose after 1 year.

Talk with your doctor about how to protect your family from JE while traveling or living in parts of Asia. To find out if the JE vaccine is recommended where you’re traveling, visit the CDC’s travel website.

Side effects are usually mild and go away in a few days. They may include:

Pain, swelling, or redness where the shot was given

Headache and muscle aches (mostly in adults)

Low fever (mostly in children)

Serious side effects from the JE vaccine are very rare.

Like any medicine, there's a very small chance that the JE vaccine could cause a serious reaction. Keep in mind that getting the JE vaccine is much safer than getting JE. Learn more about vaccine side effects.